The goal of this project is to test the hypothesis that axons innervating the dorsal 3 laminae of the spinal cord gray matter sprout in response to a partial denervation. To do this, it is necessary to devise a method for counting the synapses in these laminae. This is a stereological problem in that we must then get 3 dimensional data (numbers of synapses) from 2 dimensional data (electron micrographs). The present study presents a standard stereological method for obtaining these numbers. In the first year, we have concentrated on measuring the length of the synaptic cleft in the dorsal horn and have found that the average length is different in the different laminae. The next step is to determine synaptic numbers.